Preparation of PVDF/CaCO3 hybrid hollow fiber membranes for direct contact membrane distillation through TIPS method

Poly(vinylidene fluoride) (PVDF)-CaCO3 hybrid hollow fiber membranes with a cellular structure and prominent permeability were fabricated via the thermally induced phase separation method for membrane distillation. CaCO3 nanoparticles were introduced to the casting solution to improve the properties of the membranes. The effect of CaCO3 dosage on the morphology was investigated. The prepared membranes were characterized by differential scanning calorimetry, SEM, and atomic force microscopy. The results showed that liquid-liquid phase separation preceded solid-liquid phase separation during the spinning process. Low dosages of CaCO3 had a strong influence on the crystallization of PVDF molecules. The contact angle of the membrane increased with the addition of CaCO3 nanoparticles. The maximum dead end pure water flux was as high as 1295.5 L/(m(2) h). The direct-contact membrane distillation flux of the optimized PVDF/CaCO3 hybrid membrane achieved 63.98 kg/(m(2) h) at the feed temperature of 90 degrees C. (c) 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43372.